250 
rett, 1956: 41) of the fungus, or a waning in 
the secretion of auxin, may account for the re- 
covery from infection of some roots, which are 
then capable of bursting through the mantle and 
resuming extended growth. 
SUMMARY 
The root surface of germinating seedlings of 
Nothofagus solandri var. cliff or tioides was found 
to be colonized at an early stage by superficial 
sheets of mycelium, but intracellular penetration 
was not apparent until the stage of emergence 
of lateral roots. Radial elongation of epidermal 
cells was always found to precede penetration 
by the mycorrhizal fungus. The presence of 
massed hyphae over the root-growing point ap- 
pears to be necessary for the transformation of 
the root into a mycorrhiza. 
PACIFIC SCIENCE, Vol. XIV, July I960 
ACKNOWLEDGMENTS 
I am indebted to the University of New Zea- 
land for a research grant in aid of the work. 
REFERENCES 
Garrett, S. D. 1956. Biology of Root Infect- 
ing Fungi. Cambridge University Press. 
Harley, J. L. 1937. Ecological observations on 
the mycorrhiza of beech (Preliminary note). 
J. Ecol. 25: 421-423. 
Melin, E., and H. Nilsson. 1950. Transfer of 
radioactive phosphorus to pine seedlings by 
means of mycorrhizal hyphae. Physiol. Plant. 
3:88-92. 
Slankis, V. 1950. Effect of a napthaleneacetic 
acid on dichotomous branching of isolated 
roots of Pinus silvestris (A preliminary re- 
port ) . Physiol. Plant. 3 : 40-44. 
